The understanding of the reconstruction and calibration of electrons and
photons is one of the key steps at the start-up of data-taking with ATLAS at
the LHC (Large Hadron Collider). The calorimeter cells are electronically
calibrated before being clustered. Corrections to local position and energy
measurements are applied to take into account the calorimeter geometry.
Finally, longitudinal weights are applied to correct for energy loss upstream
of the calorimeter. As a last step the Z -> ee events will be used for in-situ
calibration using the Z boson mass. The electron identification is based on the
shower shape in the calorimeter and relies heavily on the tracker and combined
tracker/calorimeter information to achieve the required rejection of 10^5
against QCD jets for a reasonably clean inclusive electron spectrum above 20-25
GeV. For photon identification, in addition to the shower shape in the
calorimeter, recovery of photon conversions is an essential ingredient given
the large amount of material in the inner tracker. The electron and photon
identification methods (cuts and multivariate analysis) will be discussed.Comment: Poster write-up at ICHEP08, Philadelphia, USA, July 2008. 4 pages,
LaTeX, 7 eps figures, 2 rtx files, 1 sty file and 1 cls fil
